Which of the following terms best describes a beetle found in trees?

The term "arboreal" is used to describe organisms that live in trees. This term comes from the Latin word "arbor," meaning tree, and it is typically used in biological classifications to refer to animals that are adapted to life in the tree canopy, as well as some insects that inhabit these environments. In the context of beetles, many species are known to feed on wood or live in the bark and branches of trees, making "arboreal" the most fitting descriptor.

The other options do not accurately capture the relationship between the beetle and its tree habitat. "Entomological" refers to the study of insects in general and does not specifically denote a habitat. "Extinct" signifies a species that no longer exists, which does not apply here. "Terrestrial" pertains to land-based organisms, but it is too broad and does not emphasize the specific arboreal context in which the beetle is found. Thus, "arboreal" clearly indicates the beetle's association with trees.